1. Field of the Invention
This invention relates to a process and a control device for the circulation of a fluid through a fluid bypass. The invention more particularly relates to a regulation system for the supercharging air of an internal combustion engine.
2. Description of the Related Art
Bypass boxes or bypasses have been used selectively to distribute a fluid into one of two separate ducts. Generally, a bypass comprises an exterior casing or wall that delimits a fluid inlet, a main fluid outlet, a secondary fluid bypass outlet and an interior chamber for fluid in which there is placed a blocking flap pivoting between a position that closes the main outlet and a position that closes the bypass outlet. When the main outlet is blocked by the flap, the bypass is opened. When the secondary bypass outlet is blocked by the flap, the bypass is closed.
Generally, the blocking flap of the bypass is actuated by a hydraulic actuator or an electromagnetic actuator. Control of the actuator is provided by an electronically controlled system requiring numerous data sensors to respond to the operating requirements of the system.
International patent application WO 92/01145 provides for such a regulation system for supercharging air. In this document, the supercharging air exiting a turbocharger is first cooled with the help of an engine cooling liquid/supercharging air heat exchanger. The supercharging air exiting this heat exchanger goes into a bypass whose main outlet is connected to a second supercharging air/ambient air heat exchanger and whose secondary bypass outlet is connected directly to the intake manifold of the engine.
A central electronic control unit manages the data supplied by the temperature sensors: the temperature of the supercharging air entering the engine, the temperature of the combustion gases exiting the engine and the temperature of the exhaust gases, and by other sensors supplying notably the engine speed. The central control unit then electrically controls an electromechanical actuator that controls the pivoting of the blocking flap of the bypass. Such a regulation system is particularly complex and requires a large number of data sensors with a central unit managed electronically.